Some erros on jquery wp 5.7

An old book warns not to put new wine in an old wineskin 😀

Please update your theme, and your problem should go away, as your theme’s developer has updated the theme already to work with the latest version of WordPress.

Good luck!

The problem is that, the old developer seems to have changed something in the theme, and there is no option to update the theme.

Note that WordPress cannot natively handle auto-updates for commercial themes (and plugins), because the code is not hosted at WordPress.org. Commercial theme vendors implement their own update mechanism, and often require a license key.

And there are a lot of commercial themes (and plugins) out there that simply don’t support dashboard updates, and the only way to update these is to manually grab the new theme version from the vendor and upload to your server.

I have a question, if I download the (updated) theme again from the developer’s website and apply, will it resolve or will I have problems?

I can’t say for sure, as you’re using a child theme, and I don’t know what’s in the child theme. But updating the parent “XTRA” theme should be a required first step, as the theme’s changelog page linked above mentions fixing jQuery and WordPress 5.7.x compatibility. Also, note that the latest version of the theme is 4.1.0, so that’s the version that you should be upgrading to.